It is often desirable to be able to prevent use of a ladder, especially when ladders provide ready access to buildings, vehicles or towers.
On both domestic and commercial building sites, ladders are commonly left on site, overnight and on weekends, ready for use on the next working day. During this time they allow easy access to upper levels and roofs, which may be unsafe. As well as the dangers of locations able to be accessed by ladders left on site, the ladders themselves can present a hazard to unauthorised users.
Unauthorised users may be children, vandals, thieves or people wishing to survey the progress of the building works.
Ladder guards have been developed that block access to a ladder in a number of alternative ways. U.S. Pat. No. 4,126,206 discloses a ladder guard having two sheets of metal pivotally joined together. The upper sheet hooks over a rung of the ladder. The lower sheet includes a portion that engages a rung from behind. The lower sheet is locked into position to prevent removal of the guard and access to the ladder. This guard must be completely removed and installed at the beginning and end of every day.
There are a number of other ladder guards disclosed in patent specifications, that simply sit over the front of the ladder engaging one rung at one end and locking onto the ladder at the other end. As with the previously described ladder guard, each of these devices must be fully removed and installed at the beginning and end of every day. Whilst installation is relatively straightforward, the ladder guard must be retrieved from its storage location, installed onto the ladder and locked into position. This process means that many of the people working on a typical building site, such as builders and other trades people, are likely to leave at the end of the day without installing the ladder guards. That is, there is a significant disincentive to reliable daily use of the ladder guards.
U.S. Pat. No. 3,225,863 discloses a ladder guard having a panel which is hingedly mounted at one side to the ladder, such that the panel can swing around to allow or prevent access to the ladder. The ladder guard is permanently installed on the ladder and therefore a site worker would simply swing the panel across the ladder and lock it into a closed position.
While this construction overcomes the problems of a separate ladder guard, it presents new problems. The ladder guard takes up space next to the ladder when open, thus preventing the ladder from being positioned next to an access opening or doorway. The ladder guard could be easily broken as people move past it, catching things on it when in the open position. The ladder guard, when in a closed and locked position, does not prevent access to the rear of the ladder, and indeed the ladder can still be used unless it is permanently affixed to a wall.
It is therefore an object of the present invention to provide an improved ladder guard that overcomes at least some of the problems with the prior art described.
The applicant does not concede that the prior art discussed above forms part of the common general knowledge in the art in Australia at the priority date.